6c1add8b73
* Prototype support for virtual uinput devices * Tidy uinput a bit * Have all the evtest examples use the same args/prompt code * Switch to libc uinput* structs * Use InputId in uinput, use libc _CNT constants * Don't use align_to_mut * Only check /dev/input/eventN files * Spelling fixup * Fix compilation error * Ah, there we go. Much better. Co-authored-by: Jeff Hiner <jeff-hiner@users.noreply.github.com> Co-authored-by: Noah <33094578+coolreader18@users.noreply.github.com>
82 lines
2.3 KiB
Rust
82 lines
2.3 KiB
Rust
//! This example demonstrates how to use the evdev crate with a nonblocking file descriptor.
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//!
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//! Note that for this implementation the caller is responsible for ensuring the underlying
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//! Device file descriptor is set to O_NONBLOCK. The caller must also create the epoll descriptor,
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//! bind it, check for EAGAIN returns from fetch_events_*, call epoll_wait as appropriate, and
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//! clean up the epoll file descriptor when finished.
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use nix::{
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fcntl::{FcntlArg, OFlag},
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sys::epoll,
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};
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use std::os::unix::io::{AsRawFd, RawFd};
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// cli/"tui" shared between the evtest examples
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mod _pick_device;
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fn main() -> Result<(), Box<dyn std::error::Error>> {
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let mut d = _pick_device::pick_device();
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println!("{}", d);
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let raw_fd = d.as_raw_fd();
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// Set nonblocking
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nix::fcntl::fcntl(raw_fd, FcntlArg::F_SETFL(OFlag::O_NONBLOCK))?;
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// Create epoll handle and attach raw_fd
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let epoll_fd = Epoll::new(epoll::epoll_create1(
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epoll::EpollCreateFlags::EPOLL_CLOEXEC,
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)?);
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let mut event = epoll::EpollEvent::new(epoll::EpollFlags::EPOLLIN, 0);
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epoll::epoll_ctl(
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epoll_fd.as_raw_fd(),
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epoll::EpollOp::EpollCtlAdd,
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raw_fd,
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Some(&mut event),
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)?;
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// We don't care about these, but the kernel wants to fill them.
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let mut events = [epoll::EpollEvent::empty(); 2];
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println!("Events:");
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loop {
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match d.fetch_events() {
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Ok(iterator) => {
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for ev in iterator {
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println!("{:?}", ev);
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}
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}
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Err(e) if e.kind() == std::io::ErrorKind::WouldBlock => {
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// Wait forever for bytes available on raw_fd
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epoll::epoll_wait(epoll_fd.as_raw_fd(), &mut events, -1)?;
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}
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Err(e) => {
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eprintln!("{}", e);
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break;
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}
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}
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}
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Ok(())
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}
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// The rest here is to ensure the epoll handle is cleaned up properly.
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// You can also use the epoll crate, if you prefer.
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struct Epoll(RawFd);
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impl Epoll {
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pub(crate) fn new(fd: RawFd) -> Self {
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Epoll(fd)
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}
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}
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impl AsRawFd for Epoll {
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fn as_raw_fd(&self) -> RawFd {
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self.0
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}
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}
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impl Drop for Epoll {
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fn drop(&mut self) {
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let _ = nix::unistd::close(self.0);
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}
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}
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